There is known an evaporated fuel processing device described in a patent literature 1 as a conventional example one to be attached to a fuel tank for an automobile or the like. FIGS. 3A, 3B schematically show the evaporated fuel processing device, and are a plan view, a side view, respectively. The evaporated fuel processing device 31 is provided with a liquid level surface detection valve 32 and a fuel shutoff valve 33. The liquid level surface detection valve 32 has a first float valve body 35 to close a canister communication hole 34 being a valve seat when fuel is poured into the tank to be in a state of full-tank. The symbol L1 (FIGS. 4A, 4B) shows a full-tank liquid level surface. The fuel shutoff valve 33 has a second float valve body 37 to close an evaporation hole 36 being a valve seat when, for example, the vehicle body is largely inclined, so that a liquid level surface comes to be a prescribed position higher than the full-tank liquid level surface L1. The evaporation hole 36 is located at a position higher than the canister communication hole 34.
The first float valve body 35 and the second float valve body 37 are housed in a housing 38 being a valve box to be attached to the fuel tank T. The housing 38 is provided with an outlet port 39 to be connected to a canister not shown. In an upper space in the housing 38, the canister communication hole 34 and the evaporation hole 36 communicate with each other through a communication path 40. As realized from FIG. 3A, the evaporated fuel processing device 31 has a construction that the fuel shutoff valve 33, the liquid level surface detection valve 32, and the outlet port 39 are arranged on a straight line in this order from an end side.